CONCORD, N.H. — New Hampshire Fish and Game officers have two men in custody and two buckets of baby eels as evidence of what they say is part of an international eel-poaching operation believed to be driven by a worldwide shortage of eels.

Two brothers from Maine — 35-year-old Justin Kinney of Mount Vernon and 29-year-old Matthew Kinney of Bremen — are charged with taking eels without a harvest permit and taking glass eels less than 6 inches long.

Matthew Kinney also is charged with assault on a law enforcement officer, resisting arrest and disobeying a conservation officer. Officials say the younger Kinney fled with a handcuff fastened to one wrist, leading officers on a pursuit that involved dogs and a helicopter before he was apprehended at a hotel hours later.

Fish and Game Lt. Michael Eastman said only two states on the Eastern seaboard — Maine and South Carolina — allow fishing and sale of baby eels, and both require permits.

Eastman said two of his conservation officers were tipped that the brothers would be netting the baby eels in the Hampton Falls River and moved in to apprehend them shortly after 5 a.m. Friday.

“We knew what they were doing and went to make the arrests,” Eastman said.

Eastman said the brothers were compliant at first, then resisted arrest. Justin Kinney was cuffed immediately but his brother fought one of the conservation officers, fell into the river and fled through the marshland, Eastman said.

A state police helicopter searched from above and police dogs tracked Matthew Kinney until police finally caught up with him in a room at the Hampton Falls Inn, where the brothers were staying.

Matthew Kinney is being held on a $5,000 bond. Bond was set at $2,500 for Justin Kinney. Both are scheduled to be arraigned in Seabrook District Court on Monday. It wasn’t known whether they had legal representation.

Eastman said eel poaching is on the rise, driven by an increase in demand and price.

“As the price goes up, people are going to be there to do it illegally,” Eastman said.

He said the baby eels, known as elvers, command about $2,000 per pound or more. He said most are destined for Asian markets, where they are nurtured until full grown then sold to restaurants and other outlets.

Elvers are spawned in salt water then swim up rivers and grow in fresh water before migrating back to the sea to spawn, Eastman said. He said the elvers caught by the Kinneys were about 2 inches long and it was impossible to tell how many were in the two buckets.

“I want to say it takes 800 to a thousand to make a pound,” Eastman said. “They’re very small.”

Eastman would not identify the conservation officer who was involved in the struggle with Matthew Kinney, but said the officer was not injured.

Maine officials last month charged a New Hampshire man — 41-year-old Philip Parker of Candia — with possession of 41 pounds of baby eels without a permit. He is due in court later this month. Parker could not be reached for comment. No phone number in Candia was listed in his name.

In 2012, Maine Gov. Paul LePage signed emergency legislation that levies $2,000 fines and license suspensions for illegal elver fishing or tampering with other people’s gear.